Machinery for making shoes



Jan. 12, 1965 c. D. MATTERN MACHINERY FOR MAKING SHOES 2 Sheets-Sheet 1 Filed Feb. 8, 1963 Inventor Chester D. Ma zze/"n United States Patent 3,164,866 MACHINERY FQR MAKING SHOES Chester D. Mattern, Hamilton, Mass., assignor to United Shoe Machinery Corporation, Boston, Mass, a corporation of New Jersey Filed Feb. 8, 1963, Ser. No. 257,260 '1 Claim. (Cl. 18-46) This invention relates to machines for molding outsoles onto shoe bottoms, and more particularly to an improved shoe form for use in such machines.

With the development of injection molding, performed by machines of the type described in US. Patent No. 3,006,032, Baker et al., granted October 31, 1961, a new type of shoe form has come into use, performing simultaneously as a male mold member for the injection of the sole and as a last for the upper. The molding role requires that the form have a strong pedestal and mounting means for attaching it to the injection molding machine properly. The lasting role-that of stretching the upper into shape on the formhas made it desirable to provide a separate heel piece which can be retracted into a recess provided in the main body of the shoe form, although many shoe forms now in use are still of the simple, solid, one piece design. Retractability of the heel also makes the removal operation much easier, after the sole has been molded onto the upper.

The presently used retractable heel injection molding machine shoe forms have linkage mechanisms consisting of a hinge member mounted rigidly on the movable heel and pinned rotatably to the main body of the forms and a complex array of levers and arms for cranking the rotatable heel into and out of its recess in the main body of the shoe form. This arrangement has proved disadvantageous in several respects: the fact that the axis of rotation of the heel goes through the main body of the shoe form means that the molding face of the heel describes an arc of large radius as the heel rotates between the extended and the foreshortened broken positions. Since the arc of rotation of the heel determines the angle between the recess in the main body of the shoe form and the molding surface of the shoe form, the larger the radius of the arc, the less will be the angle and the thinner and more fragile will be that portion of the main body between the heel recess and the molding surface.

The less the angle between the arc of rotation of the heel and the molding surface, the greater will be the clearance between the heel molding surface and the margin of the main body molding surface nearest the heel; yet, as this clearance is increased, it leaves a larger and larger corresponding ridge on the injection molded sole. Especially in the infant sizes, the ridge left by the clearance of the shoe forms used heretofore have been so prominent that the injection molding process has not often been selected for making this type of shoe.

The linkages used heretofore have required large slots or central cores in both main form and heel; on the main body of the shoe form, these cores have necessarily extended into the instep portion of the form, thus weakening the form in the instep area. Especially with small shoe sizes and with tongueless types of shoes, such as moccasins, which require slendering of the instep to permit the finished shoe to be slipped off the form, the instep area has become so weak that the great stress arising during molding has caused frequent breakage, to an extent tending to preclude the use of the injection molding process to make these shoes.

One object of this invention is to provide a shoe form which will provide reduced clearance between the heel molding surface and the main body molding surface.

Another object is to provide a shoe form with an increased angle between the main molding surface and the top of the heel recess.

Another object is to provide a shoe form designthat avoids excessive coring in the instep area.

Another object is to provide a shoe form in which the heel portion rotates in such a way that the cut from the main molding surface into the shoe form can be straight rather than arcuate, thus lessening the expense of manufacture.

In the achievement of these objects I have provided a foreshortening shoe form comprising a main portion and a heel portion or block which is movable relatively to the main portion between a shoe form foreshortening and a shoe form extending position. The main portion has a head shaped similarly to the forepart of a shoe and'a neck extending from the head and merging into a broadened base portion. For mounting the heel block within a recess formed in the head of said main portion, a pair of spaced parallel plates is positioned in the upper portion of an opening extending heightwise of said main portion from the neck into the base and said plates extend upwardly into a recess in the heel block, For mounting the spaced plates two cross pins are fixed in the neck and arranged to extend through the upper portion of the opening therein. A third cross pin in the upper portions of the plates provides a pivotal mounting for the heel block. For shifting the heel block between its shoe form foreshortening and extending positions a crank shaft is journaled in the base and extends through the lower portion 'of the opening above referred to. A crank member fixed to the crank shaft is connected to the heel block by a link extending upwardly between the parallel plates and so positioned between the cross pins that mount the plates that the engagement of the link with the foremost of said cross pins arrests the movement of the heel block in its shoe form extending position.

A more complete understanding of the invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawings, in which,

FIG. 1 is a section through that portion of a shoe form to which my invention applies, showing the linkage Within the slotted portion of both the main body of the shoe form and the heel, the heel being in the broken position;

FIG. 2 is a section through a portion of the form on a larger scale than FIG. 1, with the heel portion in the proper position for injection molding; and

PEG. 3 is a rear elevation of the linkage assembly taken by itself.

Referring to FIG. 1, the illustrated shoe form comprises a forepart 12 and a heel part of block 14. The forepart 12 is extended downwardly in the form of a neck 13 the lower portion of which is expanded and merged into a broadened base 10 which is removably at tached by suitable screws 62 to a plate 60 corresponding to the plate of the injection sole molding machine disclosed in the Baker et al. patent hereinbefore referred to, said plate constituting an element of the carrier assembly.

For mounting the heel block 14 there are provided two vertically disposed triangular plates 20 (FIGS. 1 and 3) which are positioned in the upper portion of an angular opening 16 extending downwardly into the neck 13 and then horizontally'through the forward portion of the base 10. The plates 20 extend upwardly from the opening 16 into a recess or groove 18 formed in the lower portion of the heel block 14. Two pins 22 and 24 extend through the lower portion of the neck 13 and through the vertical portion of the opening 16 to provide a mounting for the plates 20. At their upper extremities the plates carry a cross pin 26 on which the heel block is pivotally Patented Jan. 12, 1965- mounted. For moving the heel portion 14 between the positions shown in FIGS. 1 and 2, a crank assembly is provided composed of two plates 32 rigidly fixed to a crank shaft 34 which is mounted rotatably in the main body of the shoe form. A wrench 36 is used to rotate the crank shaft by hand power. The plates 32 are pinned at 38 to a link 40, which is shown in FIG. 3 as two contiguous plates extending upwardly between the two triangular plates 20 and between the pins 22 and 2 5. The link 40 is pinned at 42 to the heel block 14. The link is notched to provide an open recess 44 of such depth and position that when the heel portion has been rotated clockwise from the broken position (shown in FIG. 1) to the precise position proper for injection molding (shown in FIG. 2) the base of the notch 44 at some point C will abut the pin 24, thus preventing further clockwise rotation of the heel block.

7 A critical point on injection shoe forms is a clearance 52 formed between a cut 54 into the main body of the shoe form and a corresponding face 56 of the heel portion. As will be discussed below, one feature of this invention is that the clearance 52 is minimized. Another feature is that the cut 54 is made at a greater angle to the molding surface 12 than was heretofore possible.

In the use of the shoe form itself, when it is desired to mount an upper upon the form for the molding of a sole thereto or to remove the sole-molded shoe from the shoe form, the heel portion 14 is retracted to the broken or foreshortened position shown in FIG. 1 by turning the wrench 36 clockwise, thus rotating the crank shaft 34 and the plates 32 clockwise. This in turn pulls the link 40 downwardly, and likewise the heel block 14.

When a work piece has been mounted on the shoe form and it is time to perform the injection molding process, the heel block 14 is rotated to its operative position by turning the crank counterclockwise, thus raising the link 40 until it is stopped by the pin 24.

It can be seen in the embodiment of my invention here disclosed that the recess 15 formed in the rear end of the forepart 12 to receive the heel block 14 does not extend into the instep portion of the shoe form. This has the great advantage of increasing structural strength and makes this type of form usable with shoes (mainly infant sizes and moccasins) that require such slender shoe form insteps that heretofore their shoe forms were too fragile to be commercially feasible. The recess 15 made possible by my new linkage, by leaving the instep of the shoe form solid so that the form can be used with minimal breakage for making infant sizes and moccasin-type shoes, extends the applicability of the injection molding process to include these new lines.

It will be seen in the embodiment here disclosed that the clearance 52 between the cut 54 into the main body of the shoe form and the corresponding face 56 of the heel portion is less than it would be if the heel were rotated through an are which intersects the molding surface 12 at the more acute angle which would result if the heel Were rotated about a point on the main body of the shoe form, for example, a point in the vicinity of the pin 22. In the latter case not only would the clearance be greater, thus causing a larger ridge to remain on the foot side of the soles molded, but also the small angle between the face of the cut 54 and the molding surface 12 on the main body of the form would tend to make this part of the shoe form fragile and liable to breakage.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combinations and arrangements of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

A foreshortening shoe form comprising a main body portion having a head which is shaped similarly to the forepart of a shoe and a neck extending from the head and merging into a broadened base, said main body portion having an opening extending heightwise thereof from the neck into the base, a heel block constructed and arranged to form in combination with the head of said main body portion a form for mounting a shoe, said main body portion being provided with a recess which provides clearance for the foreshortening and extending movements of the heel block, means for mounting the heel block comprising two parallel plates spaced apart from each other and extending heightwise of said main body portion, the lower portions of said plates being positioned within the upper part of said opening in the main body portion and the upper portions of said plates being positioned within a recess formed in the heel block, means for rigidly mounting said plates in the main body portion comprising a forward cross pin and a rear cross pin, said cross pins being fixed in the main body portion and extending through the neck and through the upper portion of said opening, a third cross pin extending through the heel block, through the recess formed therein and through the upper portions of said plates and pivotally mounting the heel block for foreshortening and extending movements, means for imparting such foreshortening and extending movements to the heel block comprising a crank shaft journaled in the base of said main body portion and extending through the lower extremity of said opening, crank means fixed to said crank shaft and positioned within said opening, a link connecting the crank means to the heel block, said link being positioned between said parallel plates and being positioned between the first cross pin and the second cross pin, said first cross pin providing a stop against which the link comes to rest upon the completion of the operation of the crank means to advance the heel block from its foreshortening position to its shoe form extending position.

References Cited in the file of this patent UNITED STATES PATENTS 864,654 Krentler Aug. 27, 1907 873,635 Thurell Dec. 10, 1907 2,929,125 McGinnis et al Mar. 22, 1960 3,040,349 Levaggi June 26, 1962 3,068,524 Klee Dec. 18, 1962 

